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Re: Sewing Frame

Nick said:
>As far as keeping tension on the cords - not so....
>Vertical tension on the cords is unnecessary....
>In fact, it's a labor-saving device that came centuries
>after the supported-sewn codex structure was developed.

Dorothy said:
>certainly by the time you get to Romanesque
>the frame is there and the tension on the cords is necessary to create a
>tight vellum text block.

What is the fact? Does anyone know for sure when a frame was first used for
sewing? If the development of certain sewn structures evolved from weaving,
it wouldn't be surprising to find wooden frames early on. Coptic flat-back
unsupported sewing wouldn't need a frame, but what evidence is there about
the techniques used to create the first supported structures?

Let's not forget that the early supported structures were not "rounded and
backed." There is a natural round which comes from consolidated sewing,
which helps relieve the swelling caused by the addition of thread, allowing
the book to be more square than wedgy. Early wooden boards were back-beveled
on the inside of the spine edge as compensation. If you are going to round
and back the book (by hammer or machine) then you have less "need" of a
frame, because you are forcing the book bo do what the consolitation helps
it do naturally. But this is a more modern technique, not an earlier one.

Patricia asks:
>What do you mean by "consolidation of the sections?"

Joe said earlier:
>The frame not only keeps the sewing
>supports in correct alignment and under tension but enables you
>to apply sufficient and consistent tension on the thread when
>sewing. More importantly it allows a consolidation of the
>sections of the book that would be impossible without the frame.
>A properly sewn and consolidated textblock will almost round and
>back itself. The book will hold its shape naturally without
>relying upon an adhesive to do what the structure was meant to do.

Consolidation occurs during sewing when you hit the sections with a weighted
stick after each section is sewn. This is an operation that is more
difficult without a sewing frame. It is not as significant in tape sewing,
and is most important in "double flexible" (see below). What you do while
sewing a book in the traditional method is whack each section between each
sewing station (i.e., between each cord or pair of cords) before adding the
next section. This consolidates the text block as Joe described. Without the
tension supplied by the frame, the cord moves with the section. The tension
on the cord allows the section to slide a bit down the cord, closer to the
previous section.

Barbara asks:
>what is a double flexible text block?

It's an English term and refers to sewing on double raised cords. "Flexible"
is the English term for "raised cord sewing." Traditionally in raised cord
sewing a tight back leather binding is added, in which the leather flexes
with the spine. In tape or "sawn-in" cord sewing, a hollow tube is applied
to the spine or a case binding is used, in which the spine of the case or
the leather spine separates from the text spine when the book is open. The
leather then does not flex.


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